Hand-held wall receptacle wiring tester with oppositely disposed push/pull surfaces for insertion and removal of the tester

ABSTRACT

A hand-held electrical tester for checking the wiring of a wall receptacle. The blades of an electrical terminal protrude from one end of a housing which contains indicator lamps and electrical connecting means between the lamps and blades. Thus, the lighting of each lamp or combination of lamps indicates a predetermined wiring condition of a wall receptacle in which the terminal blades may be inserted. The housing is shaped to provide oppositely disposed push/pull surfaces to facilitate insertion and removal of the tester into and from a wall receptacle.

SUMMARY OF THE INVENTION

This invention relates in general to electrical testing equipment andmore particularly to a hand-held tester for checking the wiring of awall receptacle.

A hand-held receptacle wiring tester is provided which includes ahousing having first laterally opposite surfaces which spreadincreasingly apart toward one end of the tester and second laterallyopposite surfaces which spread increasingly apart toward the other endof the tester to provide bearing surfaces for respectively pushing thetester into a receptacle and pulling it out. A set of electricalterminal blades protrude from one end of the housing in order to beplugged into a wall receptacle. The housing contains indicator lamps andelectrical connecting means between the lamps and respective pairs ofthe terminal blades so that the lighting of a lamp and variouscombinations of lamps indicates respective predetermined wiringconditions of the wall receptacle.

Variations of the basic tester include separate enclosed compartmentswithin the housing for each lamp and semi-recessed protective lensesover the lamps. The first and second laterally opposite surfaces may beon the same or different sides of the housing and may be provided with asurface treatment to prevent slippage as the tester is pushed into orout of a wall receptacle. The housing may be longitudinally split sothat the tester can be substantially assembled in one half beforeclosing it with the other.

A primary object of the present invention is a hand-held receptaclewiring tester which is provided with non-slip push/pull surfaces tofacilitate insertion of the tester into a wall receptacle and itsremoval therefrom.

A related object is a hand-held receptacle wiring tester having ahousing with push/pull surfaces which may be utilized with a single gripof the tester.

Another object is a hand-held receptacle wiring tester in which theterminal blades are held by the housing at two points spacessubstantially apart, thereby affording a holding leverage which protectsthe housing and maintains the blades in their fixed positionalrelationship.

Another object is a hand-held receptacle wiring tester which issubstantially flat so that it may be easily carried in an electrician'spocket or pouch.

Another object is a hand-held receptacle wiring tester in which thelegend which indicates the wiring condition of the receptacle is placedon a single, generally flat surface so as to be entirely visible at aglance.

Another object is a hand-held receptacle wiring tester in which theindicator lamps are protected by semi-recessed lenses which are thusvisible from various angles and yet protected laterally by the walls ofthe tester housing.

Another object is a hand-held receptacle wiring tester having separateinternal compartments for the indicator lamps to prevent diffusion oflight from one lamp through the lens of another.

Another object is a hand-held receptacle wiring tester in which theterminal blades, lamps and electrical connector means may be assembledin a casing portion of the housing and be entirely visible forinspection prior to closing and sealing the housing with the coverportion.

Another object is a hand-held receptacle wiring tester which is durable,light-weight and somewhat fitted to the hand of an electrician tofacilitate the testing of wall receptacles.

Other objects will become apparent in the ensuing specification,drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of a receptacle wiring tester constructed inaccordance with the present invention.

FIG. 2 is a side view of the receptacle wiring tester of FIG. 1.

FIGS. 3 and 4 are end views of the receptacle wiring tester shown inFIGS. 1 and 2.

FIG. 5 is an enlarged bottom view of the receptacle wiring tester withthe cover portion of the housing removed.

FIG. 6 is a side sectional view taken approximately along line 6--6 ofFIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A hand-held electrical tester 10 for checking the wiring of wallreceptacles is shown in FIGS. 1-6. The tester includes a housing 12having a set of electrical terminal blades protruding from one end 14.The terminal blades include two parallel flat blades 16 (hot) and 18(neutral) and a generally U-shaped ground blade 20. The terminal blades,which are arranged in the conventional fixed positional relationship forinsertion into a wall receptacle, are mounted within the housing in amanner described in further detail below. Referring to FIGS. 5 and 6,the housing also contains three indicator lamps 22, 24 and 26, andelectrical connecting means between each lamp and a respective pair ofthe terminal blades so that the lighting of each lamp and eachcombination of lamps indicates a predetermined wiring condition of awall receptacle into which the terminal blades may be inserted.

Housing 12 has first laterally opposite surfaces 28 (FIGS. 2 and 6)which spread increasingly apart toward end 14 of the tester and secondlaterally opposite surfaces 30 (FIGS. 1 and 5) which spread increasinglyapart toward the other end of the tester, which surfaces provide bearingsurfaces for respectively pushing the tester into a receptacle andpulling it out therefrom. The first and second laterally oppositesurfaces are each shown as a pair of surfaces which are generallysymmetrically situated with respect to a longitudinally center linethrough the housing 12 which would intersect end 14. The first laterallyopposite surfaces or push surfaces 28 are oppositely disposed ondiametrically opposed sides of the tester housing 12. The secondlaterally opposite surfaces or pull surfaces 30 are similarly disposedbut on different sides of the housing from each other and from the pushsurfaces 28. Although the illustrated form is preferred, the push andpull surfaces 28 and 30 might otherwise be formed as continuous oval orannular surfaces around the housing 12 or discontinuous arcuatesurfaces. Likewise, the push and pull surfaces 28 and 30 could each beformed on all four sides of the housing or on all or only some of thesides of any other multi-sided housing. The important point is that thesurfaces flare outwardly from the surface of the housing toward one endor the other to form bearing surfaces against which an electrician canpush or pull to facilitate using the tester. Again, it is preferred thatthe push surfaces 28 be longitudinally positioned closer to the end 14of the tester than the surfaces 30, but this could be otherwise.

In FIGS. 1, 2 and 4, push surfaces 28 are shown with a plurality ofspaced ridges 32 formed laterally across each surface. The purpose ofthese ridges is to prevent slippage of the electrician's grip on theconnector as he pushes it into a wall receptacle. The particular designof the ridges is not critical, but rather any non-slip surface treatmentcould be substituted which would increase the frictional contact betweenthe push surfaces 28 and the electrician's hand. Thus, the surfacesmight be knurled, foraminated or otherwise coarsened. The same ordifferent surface treatment may be applied to one or both of the firstand second sets of laterally opposite surfaces 28 and 30.

The housing 12 is longitudinally split, as best shown in FIGS. 2 and 3,and thereby consists of a casing portion 34 and cover portion 36. Thefront wall 37 (FIG. 3) of casing 34 is provided with two parallel slots38 adapted to receive and properly position the flat blades 16 and 18. Aground support member 40 projects downwardly away from the slots 38 toreceive and properly position ground blade 20. The terminal end 14 ofcover 36 is provided with cooperating shoulders 42 for retaining flatblades 16 and 18 in their respective slots 38 and a center shoulder 44for retaining the ground blade 20 within ground support member 40. Theother end of the casing and cover portion is generally open forreceiving three lenses 46, 48 and 50 which are described in furtherdetail below.

The internal construction and components of receptacle tester 10 arebest shown in FIGS. 5 and 6. The terminal blades extend inwardly fromthe terminal end 14 of the tester and through a blade-retainer wall 52.Like the front wall 37 of casing 34, wall 52 is slotted to receive flatblades 16 and 18 and has a downwardly extending ground blade supportmember 54. Ground blade retainer wall 52 serves not only to retain theblades in their proper positional relationship, but also as a memberthrough which longitudinal forces are applied to the terminal blades topush them into a wall receptacle.

The shape and assembled position of the flat terminal blade 16 is shownbest in FIG. 6. The other flat terminal blade 18 may be constructed andmounted similarly. Basically, the blade has three integral sections: aterminal plug portion 56, a center section 58 and an inner wrap-aroundconnector section 60. The terminal plug portion 56 is adapted to extendlongitudinally outwardly from casing 34 through one of the slots 38 forthe purpose of being plugged into a wall receptacle. Thus the dimensionsof plug portion 56 are conventional. The outer tip 62 may be rounded andtapered to further ease insertion into the typically stiff wallreceptacles found in new construction. The center section 58 is enlargedvertically above and below the terminal plug section 56. Thus a shoulder64 is provided which is adapted to abut against the front wall 37 ofcasing 34 to prevent the terminal blade from being pulled longitudinallyout of the housing. The inner end of center section 58 is receivedwithin a slot 66 in retainer wall 52, which slot provides longitudinalrestraint to prevent the terminal blade from being pushed into thehousing. The slots 38 and 66 in casing 34 both provide the lateralrestraint necessary to maintain the proper and uniform spacing betweenflat blades 16 and 18. Slot 66 is shown as being stepped at 67 to allowthe middle section 58 of the terminal blade to be seated partiallywithin retainer wall 52 while allowing the connector portion 60 toextend completely through the wall and further into the housing.Connector section 60 has two vertically semi-circular indentations 68adapted to receive wires for making an electrical connection with theterminal blade. The flat blades 16 and 18 are vertically restrained inthe assembled housing in a number of ways. First, the cover portion 36has a front wall 70 with shoulders 42 which are adapted to close slots38 of the casing and restrain the terminal blades therein. The centersection 58 of the terminal blade is fitted between slot 66 in retainerwall 52 and the front wall 37 so that vertical rotation is restricted.But to further restrict vertical movement of the blade at the retainerwall 52, it is preferred that the blade be staked into slot 66 byclosing the retainer wall over the slot such as by heat staking orultrasonic staking.

The shape and installed position of ground blade 20 can likewise be seenin FIGS. 5 and 6. Extending longitudinally outwardly from ground supportmember 40 on the front wall 37 of the casing, the ground blade isgenerally U-shaped in the conventional manner for insertion into theground slot of a wall receptacle. Inwardly of front wall 37, the groundblade becomes flattened prior to reaching retainer wall 52. Theflattened middle portion 74 of ground blade 20 is wider (FIG. 5) thanthe center slot 76 in retainer wall 52. Therefore, two laterallyopposite indentations 78 are formed in the ground blade so that it maybe fitted into slot 76. Ground blade 20 also has a wrap-around connectorsection 80 at its inner end. Longitudinal restraint for the ground bladein its assembled position is provided by the edges of the indentations78 which abut against both sides of retainer wall 52. Lateral restraintfor the ground blade is provided by the sides of the ground supportmember 40 at the front wall 37 and by the sides of slot 76 in retainerwall 52. Vertical restraint is provided by shoulder 44 of cover 36 atthe front wall and by staking the ground blade in position at theretainer wall by at least partially closing slot 76 over the groundblade.

Looking at the other end of the housing in FIGS. 5 and 6, both thecasing 34 and cover 36 are provided with cooperating longitudinaldividing walls 82 and 84 respectively, which walls are generally equallyspaced from the sides of the tester and from each other to form threeseparate compartments for lamps 22, 24 and 26. In their assembledpositions as shown in FIG. 6, walls 82 and 84 abut against one anotherto prevent the diffusion of light from one lamp into the compartment ofanother.

To further enclose the lamp compartments, a wall 86 laterally spans thecover 36 in engagement with the inner ends of walls 84. Likewise,housing 34 is provided with a similarly disposed lateral wall 88 which,however, is shorter than the longitudinal walls 82 to provide a gapbetween walls 86 and 88 through which the terminal portion 90 (FIG. 6)of the lamps may extend. The divider walls 82 and 84 also have laterallyspaced slots 92 intermediate their length, which slots are adapted toreceive and retain a lamp retainer 94. The lamp retainer 94 is a thin,flat member of cardboard, plastic or any other suitable material havingthree laterally spaced holes which are adapted to receive the lamps 22,24 and 26 to support them in a generally centralized position within thecompartments.

Between the terminal blade retainer wall 52 and lamp compartments, thecasing 34 and cover 36 are generally open to accommodate the electricalconnecting means between the lamps and terminal blades. The onlyinterference within this area is the peg and sleeve connections betweenthe cover 36 and casing portion 34 of the housing. The cover is providedwith a pair of spaced apart vertically directed pegs 96 which areadapted to be received within cooperating sleeves 98 of casing 34 to fixthe lateral and longitudinal positional relationship between the coverand casing in the assembled receptacle tester. The peg and sleeveconnections are further advantageous for separating the variouselectrical connecting means between the lamps and terminal blades.

The aforementioned electrical connecting means includes the wires,resistors and insulative tubing necessary to complete the electricalconnections between each lamp and a respective pair of the terminalblades. Preferably, resistor attached glow lamps which may be utilizedhave a resistor 100 pre-connected along one of the lead wire 102 of eachlamp. Thus, the only assembly required is insulating certain crossoverwires and electrically connecting each lead wire to a terminal blade. Inthe preferred embodiment, a 0.25 watt lamp is used having an attached22K Ohm register. Referring to FIG. 5, the resistor attached lead 102and plain lead 104 of lamp 22 are connected respectively to the hotblade 16 and ground blade 20. Likewise, the leads of lamp 24 areconnected respectively to ground blade 20 and neutral blade 18. Finally,the leads of lamp 26 are connected respectively to neutral blade 18 andhot blade 16 to complete a parallel circuit between the lamps andblades. In the crossover area of the casing between sleeves 98 aninsulative tubing 106 may be used to cover the plain lead of lamp 26 toinsulate it from and separate the leads of the center lamp 24.

The actual connection to each terminal blade is accomplished by wrappingan end of a wire about the wrap-around connector portion of the blade asat 60 in FIG. 6 with respect to the hot blade 16. The wire is held inthe semi-circular indentation 68 to prevent it from slippinglongitudinally off the blade. It is preferred that the wires also besoldered to their respective blades to insure a strong mechanical andelectrical connection to the blades.

To complete the receptacle tester assembly, a set of generallythree-sided lenses 46, 48 and 50, are fitted onto the open ends of thelamp compartments to close the same and protect the lamps therein. Across-section of lens 46 is shown in FIG. 6.

Each lens has a generally flat outer surface 108 with side walls 110which taper vertically into the housing 12 at an angle conforming to thetapered ends 112 of the housing sidewalls shown in FIG. 2. The sidewalls 110 are formed with a shoulder 113 which is adapted to abutagainst the end of the casing 34 or cover 36. Extending into the housingfrom shoulders 113 are legs 114 having vertically directed feet 116which are adapted to engage lips 118 formed in the casing 34 and cover36 to rigidly secure the lenses over the lamp compartments. In FIGS. 1and 2, it can be seen that the open sides of lenses 46 and 50 areprotected by the sidewalls of housing 12 and that the lenses protrudelongitudinally beyond the housing by a distance approximating thethickness of the lens. The other sides of the lenses are protected bydivider walls 82 and 84. It is preferred that the lenses be constructedof translucent plastic and each of a different color to aid inidentifying the particular lamp or combination of lamps which light upwhen the tester is plugged into a wall receptacle. Thus lenses 46, 48and 50 may be clear, red and amber respectively. Accordingly, it is thelighting of the clear and amber lamps which indicates that the wiring ofa receptacle is corret. The other combinations are as follows:

    ______________________________________                                        Color          Wiring Condition                                               ______________________________________                                        Amber only     Open                                                           Amber and red  Reversed polarity                                              None           Open hot                                                       Clear only     Open neutral                                                   Red and clear  Hot and ground reversed                                        Red only       Hot on neutral with hot open                                   ______________________________________                                    

To identify which wiring condition is designated by which combination oflamps, an appropriate label may be attached to a flat surface 120 on thehousing adjacent the lenses between the pull surfaces 30. Surface 120may be slightly recessed into the housing as shown in FIG. 6 to protectthe edges of the label. A laminated label with a pressure-sensitiveadhesive backing may then be applied to surface 120, which label wouldgenerally fill the recess of surface 120 and be flush with the housingsurface.

To assemble receptacle tester 10, casing 34 is laid open-side-up as seenin FIG. 5. Insulative tubing 106 is slid onto the plain lead of lamp 26after which the leads of all the lamps are electrically connected totheir respective terminal blades. Flat blades 16 and 18 are then pressedinto position within slots 38 of front wall 37 and slots 66 of terminalblade retainer wall 52. Ground blade 20 may then be inserted so that itsgenerally U-shaped outer portion is supported within the ground bladesupport 40 (FIG. 3) and so that the indentations 78 of the inner flatportion of the blade are fitted over the ground blade support portions54 of retainer wall 52. Lamp retainer 94 may then be inserted over lamps22, 24 and 26, to properly space them for insertion into the lampcompartments of the casing 34. Lamp retainer 94 is pressed into slots 92in the divider walls 82 of the casing 34. The resistors 100 and leadwires 102 and 104 for each of the lamps may then be pressed into thecasing about sleeves 98. The lead wires are sufficiently bent to alloweach lamp to be longitudinally positioned so that its terminal portion90 overlies the inner lateral wall 88 which partially closes each lampcompartment in casing 34.

To rigidly secure the terminal blades in their fixed positionalrelationship, it is preferred that the blades be staked securely atretainer wall 52. This may be accomplished by heat staking, ultrasonicstaking or any other mechanical means for closing slots 66 over flatblades 16 and 18 (FIG. 5) and at least partially closing slot 76 overground blade 20.

With the blades, lamps and electrical connecting means thus assembled inthe casing portion 34 of housing 12, the lenses 46, 48 and 50 and cover36 may then be added to complete the receptacle tester assembly. Thelenses are inserted between the casing 34 and cover 36 so that the lips118 of both portions of the housing will engage the small inner feet 116of the lens as the housing is closed to thereby securely retain thelenses at the end of the housing. To properly align cover 36 over casing34, both laterally and longitudinally, it is simply necessary to insertpegs 96 properly into sleeves 98. The housing portions are then pressedtogether to close and seal the housing. It is preferred that the housingportions be permanently sealed together to rigidify the tester unit sothat it may best withstand the abuse it is likely to incur in use in thefield. It is preferred that the housing sections 34 and 36 beultrasonically joined together, although a heat-seal adhesive or othersuitable means may be otherwise used. To ultrasonically join the housingsections, six so-called energy directors 122 (FIG. 5) are formed alongthe edges of casing 34 which will contact the cover 35. Two of theenergy directors 122 are formed on the divider walls 82 between the lampcompartments. The energy directors 122 are simply thin raised integralportions of the casing material which preferably rise to a point. As thehousing portions are joined, the material of the energy directors 122 isfused to that of the cover 36 to form a unitary enclosed housing.

The use, operation and function of the invention are as follows:

The present invention is useful for quickly and easily checking thepolarity or wiring condition of a conventional three-prong electricalwall receptacle. To do this, the terminal blades of the receptacletester are inserted into the wall receptacle in the same manner as theplug of any electrical appliance. As a result, a lamp or combination oflamps which corresponds to the wiring condition of the receptacle willlight up to indicate this information to the electrician or inspectorusing the device. If no lamp lights up, either the hot terminal of thereceptacle is open or no power is being supplied to the receptacle.

Checking receptacles with the tester device of the present invention hasseveral significant advantages. First, checking may be accomplishedquickly since the receptacle plate need not be removed nor thereceptacle itself pulled away from the wall for visual inspection. As aresult, all of the receptacles of a particular construction job may betested in the time it may previously have taken to spot-check only aportion of them.

One of the difficulties of checking the wiring of wall receptacles innew construction, even with a hand-held receptacle tester, is that thenew receptacles commonly are very stiff and resist the insertion of aplug or tester device such as the present invention. To overcome thisdifficulty, the present invention is provided with laterally opposedpush-pull surfaces to strengthen the grip of the electrician on thetester and thereby facilitate its insertion into a receptacle. The pushsurfaces 28 are somewhat steep and provided with a surface treatmentsuch as the ridges 32 to prevent slippage of the electrician's handwhile inserting the tester. Since the force required to remove thetester from a receptacle is generally less than that needed forinsertion, the pull surfaces 30 may be gently sloped outwardly from thesurface of the housing so as to comfortably conform to the grip of theelectrician using the device. Primarily for this purpose of somewhatfitting the tester to an electrician's hand, it is preferred to have thepush surfaces 28 located closer to the terminal end 14 of the housingand on different sides of the housing from the pull surfaces 30. Withsuch a construction, the push and pull surfaces are both effective toassist an electrician using a single grip on the tester to both insertand remove the tester from a wall receptacle in one motion, which is allthat is necessary to precisely check the wiring of the receptacle.

It is also preferred that the push and pull surfaces be formed ondifferent sides of the housing so that neither interferes with the useof the other. Whereas it is desirable to minimize the size of thehousing and yet accommodate the different sizes of hands and styles ofgrips of many individuals, segregating the bearing surfaces on differentsides of the housing accommodates every user. Futhermore, since thatportion of the housing behind each bearing surface is narrower than thebearing surface itself, the operator's hand comes naturally to restagainst the appropriate bearing surface when using the tester device. InFIG. 1, it can be seen that the terminal end 14 of the housing issomewhat narrow and widens smoothly and gradually toward the other endto a point where the slope is increased to form each bearing surface 30.Similarly, turning the device 90° as seen in FIG. 2, the lamp end of thehousing is flared as at 112 and maintains a somewhat narrow flatthickness toward the terminal end of the housing to the point where thepush surfaces spread increasingly apart to provide bearing surfaces forinserting the tester device.

The housing 12 is constructed with several features to increase itsuseful life as well as facilitate the use of the device. By securelyholding the terminal blades both at the front wall of the housing and atthe terminal blade retainer wall 52, a definite holding leverage isprovided which increases the force necessary to divert the terminals outof their fixed positional relationship.

Each terminal blade may be viewed as a lever mounted between front walls37 and 70 which serve as a fulcrum. Thus, the further apart the frontwall 37 and terminal blade retaining wall 52 are, the less the force isthat will be applied to the housing in response to forces actingexternally of the housing on the terminal blades. This is because of thegreater leverage within the housing. As a result, deformation of theplastic housing is less likely because of the lower forces and theuseful life of the tester device is increased.

The lamp lenses 46, 48 and 50 are constructed to both improve thevisibility of the lamps of the test device and protect them frommechanical impact. Since the lenses are semi-recessed longitudinallyoutwardly from housing 12, they can be seen from all four sides and thevisible end of the tester when it is inserted into a wall receptacle.Thus, regardless of the orientation of the receptacle on the wall, theelectrician can simply look down from a comfortable position above thetester to see which lamps are lit. But the lenses are not recessed sofar as to form an external bulb which itself is subject to fracturing.Rather, the lenses protrude longitudinally beyond the housing by adistance approximating the thickness of the lens so that only solidbodies of the lens material are exposed. Otherwise, the entire sides ofall three lenses are completely shielded and protected by the flaredends 112 and divider walls 82 and 84 of the housing.

Assembly of the tester device of the present invention is greatlyfacilitated by providing a longitudinally split housing comprised of aseparate casing 34 and cover 36. First, the casing is completely open sothat each of the lamps, blades and electrical connecting means can bedirectly placed into their fixed positions within the casing as opposedto fishing them in from one end or the other. Secondly, because thecasing is completely open before closing it with cover 36, all of theassembled elements can be visually inspected prior to closing andsealing the housing.

Finally, the wiring condition of a given receptacle can be immediatelyapparent, even to one unfamiliar with the receptacle tester since alabel identifying the respective wiring conditions may be prominentlydisplayed on the single large flat surface 120 formed into housing 12.The entire label is visible at a glance and the tester body need not berotated or turned to read any portion of the label.

Whereas the preferred form of the invention has been described herein,it should be realized that there may be many modifications,substitutions and alterations thereto.

I claim:
 1. In a hand-held receptacle wiring tester, a housing, twogenerally parallel flat blades and a ground blade mounted within thehousing and protruding from the wall at one end thereof in fixedpositional relationship for insertion into a wall receptacle, said flatblades each having a first shoulder adapted to abut against said wall ofthe housing from within to prevent the blade from being pulled out ofthe housing, and a second shoulder spaced longitudinally from the firstshoulder and adapted to abut against an internal retaining wall of thehousing to prevent the blade from being pushed into the housing, aplurality of indicator lamps at the other end of the housing andcontained within the housing, electrical connections between the lampsand the blades so that the lighting of the lamp and various combinationsof lamps indicates respective predetermined wiring conditions of a wallreceptacle into which the terminal blades are inserted, the housinghaving first laterally opposed surfaces on the exterior thereof whichspread increasingly apart toward the said one end of the tester andsecond laterally opposed surfaces which spread increasingly apart towardthe other end of the tester, thereby to provide bearing surfaces forrespectively pushing the tester manually into a receptacle and pullingit out therefrom, each of the first and second surfaces comprising apair of surfaces which are generally symmetrically situated with respectto a longitudinal center line through the housing, the first and secondpairs of surfaces being on different sides of the housing and limitedthereto, the first laterally opposed surfaces being longitudinallypositioned closer to said one end of the tester than the secondlaterally opposed surfaces with the first and second laterally opposedsurfaces being in axial nonoverlapping relationship to each other.
 2. Ahand-held receptacle wiring tester according to claim 1 wherein at leastone pair of said laterally opposite surfaces are provided with anon-slip surface treatment to prevent slippage during insertion orremoval of the tester.
 3. A hand-held receptacle tester according toclaim 1 wherein the housing is longitudinally split and therebycomprises a casing portion and cover portion, said casing portionincluding means for supporting the terminal blades, lamps and electricalconnecting means independent of assembly with the cover portion.
 4. Ahand-held receptacle wiring tester according to claim 3 wherein each ofthe terminal blades engages the housing at two points spacedsubstantially apart longitudinally along the blades thereby providing aholding leverage which increases the force necessary to divert theterminals out of their fixed positional relationship.
 5. A hand-heldreceptacle wiring tester according to claim 3 further comprising atranslucent lens overlying each of said lamps and separate substantiallyenclosed internal compartments within the housing for each lamp toprevent diffusion of light from one lamp through the lens of another. 6.A hand-held receptacle wiring tester according to claim 5 wherein eachlamp lens is semi-recessed outwardly from the housing by a distanceapproximating the thickness of the lens and wherein the housing wallslaterally protect the lens.